Hydraulic system for tractor mounted apparatus



June 16, 1959 J. s. PILCH HYDRAULIC SYSTEM F OR TRACTOR MOUNTED APPARATUS Filed Nov. 27, 1956 v H mH w C P m Vu o q, mp 4w v A h s June 16, 1959 J. s. PlLCH 2,

HYDRAULIC SYSTEM FOR TRACTOR MOUNTED APPARATUS Filed Nov. 2'7, 1956 3 Sheets-Sheet 2 INVENTOR.

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A TTOP/VEY June 16, 1959 J. s. PILCH 2,890,805

HYDRAULIC SYSTEM FOR TRACTOR MOUNTED APPARATUS Filed Nov. 27, 1956 3 Sheets-Sheet 3 INVENTOR. JOH [\l S. 'PILCH A T TOP/V04 United States Patent HYDRAULIC SYSTEM FOR TRACTOR MOUNIED APPARATUS John S. Pilch, Ware, Mass.

Application November 27, 1956, Serial No. 624,538

4 Claims. (Cl. 214-138).

This. invention relates to new and useful improvements in hydraulically actuated accessories such as trenchers or loaders or the like and the principal object is to provide an arrangement whereby upon the striking of an obstruction by the bucket during the loading or filling thereof, the bucket will be automatically raised an amount sufficient for the bucket to clear the obstruction.

Another object is to provide a hydraulic system incorporating valve means for automatically diverting the hy draulic pressure from the bucket actuating cylinder to the bucket raising cylinder, should actuation of the. bucket be interrupted by the striking of an obstruction bythe bucket.

Another object is to provide a device of the type set forth which is relatively simple and economical and which can be, incorporated in apparatus now in use.

Other objects and advantages. of the invention will be apparent from the following description taken in connection with the accompanying drawings, wherein a form Of the invention has been shown by way of illustration only.

Referring to the drawings:

Fig. 1 is a side view of an apparatus embodying the invention;

Fig. 2 is a fragmentary view of the apparatus of Fig. 1, but on anenlarged scale;

Fig. 3 is a sectional view of the valve employed; and

Fig. 4 is a schematic view of the hydraulic system of the apparatus of Figs. -1 and- 2. V V flReferring; more particularly to the drawings wherein similar reference characters designate corresponding parts throughout, the apparatus shown in Fig. 1 comprises the tractor on which is mounted a loader comprising loader arm means 11 of which a pair are usually provided with a bucket 12 pivotally connected at 13 to arms 11. Arms 11 are pivotally connected at 14 to supports 15 on the tractor.

Bucket 12 is adapted to be rotated about arms 11 by hydraulic means consisting of cylinder 16 pivotally connected at 17 to support 15 and ram 18 connected through link 19 to the bucket. Link 19 is pivotally connected at its opposite ends to ram 18 and bucket 12 and link 20 is provided for allowing a greater degree of rotation of the bucket. Link 20 is pivotally connected at its opposite ends to link 19 and arm 11 respectively and acts to guide ram 18 away from arm 11 during the pivoting of the bucket.

While only a single arm 11, and links 19 and 20 are shown, as well as a single cylinder 16 and ram 18, it is understood that usually a pair of such members are provided, or set, on each side of the tractor.

The trencher apparatus shown comprises a support 21 adapted to be connected to a tractor support and the support 22 is pivotally connected to support 21 by vertical pivots 23 and boom 24 is pivotally connected to support 22 by horizontal pivot 25.

Adjacent the outer or free end of boom 24 a dipper stick 25a is pivotally connected intermediate its ends by pivot 24' and bucket 26 is pivotally connected to the p 2,899,805 Patented June 16, 1959 "ice lower end of dipper stick 25a at 27. It is clear, therefore, that the digging operation is performed principally by pivoting bucket 26, about pivot 24', by means of dipper stick 25a. This operation develops a counter torque at pivot 24' caused by resisitance of the earth to the digging operation.

Hydraulic cylinder and ram 28 and 29 are provided between boom 24 and support 22 whereby the boom may be raised and lowered. Cylinder 28 and ram 29 are of the double acting type.

For pivoting dipper stick 25a relative to boom 24 there is provided the hydraulic cylinder 30 and ram 31, which are pivotally connected to boom 24 and dipper stick 25a respectively at 32 and 33 respectively.

For rotating bucket 26 relative to dipper stick 25a there is provided hydraulic cylinder 33a and ram 34 which is connected to bucket 26 through link 35. Link 36 is connected to dipper stick 25a and ram 34 to provide a greater degree of rotation of bucket 26 relative to dipper stick 25a.

To provide hydraulic power for cylinder 28, the hydraulic lines 36 and 37 are provided and are connected to cylinder 28 adjacent its opposite ends.

Hydraulic cylinder 33a is adapted to receive hydraulic power through lines 38 and 39 which are connected thereto adjacent its opposite ends, and cylinder 30 is adapted to receive power through lines 40 and 41 which are connected thereto adjacent its opposite ends.

During the digging or loading of bucket 26, should the bucket 26 encounter a stone or other obstruction, it is necessary that boom 24 be raised in order that the bucket may clear the obstruction to allow it to continue rotating to filling position.

The present invention relates to the provision of means whereby such raising of the boom 24, dipper stick and thereby the raising of the bucket 26 is automatically effected upon the striking of an obstruction by the bucket, whereupon the bucket is lifted until it clearsv the obstruction, at which time the raising of the boom, dipper stick and. bucket is discontinued and the bucket completes its rotation or filling.

This object is accomplished by the provision of a valve member designated generally at 42' which has an inlet 43 connected to line 41,- whereby should the bucket 26 strike an obstruction, any further hydraulic fluid under pressure applied to the rear of cylinder 30 will flow through line 41a to valve 43 and open inlet check valve 44 and pass into bore 45 in valve 42. Such fluid will then open bore check valve 45 and pass through outlet 46 and line 47 to the forward end of cylinder 37 and actuate piston 29 to raise boom 24 until the bucket 26 clears the obstruction, at which time such fluid will be employed to actuate piston 31 for continued rotation of the dipper stick and bucket about pivot 24 and any raising of the boom will be automatically discontinued.

In bore 45a is provided valve 48 having the valve portion 49.

Valve 42 has outlet 50 connected to return line 51 to the oil reservoir 52 and outlet 53 is connected to line 36 which extends between the rear of boom actuating cylinder 28 and its respective control valve.

It will be seen that excess pressure in chamber or bore 45a will automatically move piston 48 against the force of spring 54 whereby fluid may return from the rear of boom control cylinder 28 through line 36 past valve portion 49 and through return line 50 to the oil reservoir.

In operation, inlet check valve 44 for relief valve 42 would preferably be set at a slightly lower pressure than the relief valve on the control valves, for example, where the relief valve on the control valve bank is set at 1500 p.s.i., inlet valve 44 for relief valve 42 would be set at 1400 psi.

From the foregoing it will be seen that should the bucket strike an obstruction, that the continuance of pressure to either cylinder 30 or 33a will, by reverse torque about pivot 24' against cylinder 30, effect the diversion of such continued pressure to the reliefvalve, and, then to the front end of the boom'lifting cylinder to automatically effect the lifting or raising ofthe boom and thereby raise the bucket over the obstruction, at which time the lifting or raising of the boom is discontinued and the rotation of the bucket continues to bucket loading position.

From the foregoing, it will be seen that I have provided new and improved means for obtaining all of the objects and advantages of the invention.

I claim:

1. In a device of the character described, a support, a boom pivotally connected to said support for movement in a vertical direction, a dipper stick pivotally connected to said boom, a bucket carried by said dipper stick, first hydraulic means for pivoting said boom relative to said supsecond hydraulic means for automatically effecting operation of said first hydraulic means by diverting hydraulic fluid from said second hydraulic means to said first hydraulic means to thereby raise said boom and bucket if the pivoting of said dipper stick by said second hydraulic means is interrupted by the striking of an obstruction by said bucket.

2. In a device of the character described, a support, a boom pivotally connected to said support for movement in a vertical direction, a dipper stick pivotally connected to said boom, a bucket carried by said dipper stick, first hydraulic means for pivoting said boom relative to said support to raise and lower said boom and bucket, second hydraulic means for pivoting said dipper stick relative to said boom, said first and second hydraulic means each including a cylinder and a double acting piston therein, hydraulic lines connected to each of said cylinders on opposite sides of the piston in the cylinder and valve means operatively connected to said hydraulic lines for said first and second hydraulic means whereby said boom raising cylinder will be automatically actuated to raise said boom an amount necessary for said bucket to clear an obstruction upon the striking of said obstruction by said bucket 41 upon the pivotal movement thereof by said dipper stick by diverting hydraulic fluid from said second hydraulic means to said first hydraulic means.

3. In a device of the character described, a support, a boom pivotally connected to said support for movement in a vertical direction, a dipper stick pivotally connected to said boom, a bucket carried by said dipper stick, first hydraulic means for pivoting said boom relative to said support, second hydraulic means for pivoting said dipper stick relative to said boom, said first and second hydraulic means each including a cylinder and a double acting piston therein, hydraulic lines connected to each of said cylinders on opposite sides of the piston in the cylinder, and valve means operatively connected to the hydraulic line which is connected to the first hydraulic means for raising said boom and to the hydraulic line connected to the second hydraulic means on the side of the piston to etfect loading of said bucket, whereby upon the striking of an obstruction by said bucket during the loading thereof, fluid under pressure will pass from said bucket loading hydraulic line to said boom raising cylinder to thereby automatically effect raising of said boom and bucket an amount sufiicient to allow further loading of said bucket.

4. In a device of the character described, a support, a boom pivotally connected to said support for movement in a vertical plane, a dipper stick pivotally connected to said boom, a bucket pivotally carried by said dipper stick, first hydraulic means for pivoting said boom relative to said support to raise said boom, second hydraulic means for pivoting saiddipper stick relative to said boom, third hydraulic means for pivoting said bucket with respect to said dipper stick, hydraulic lines connected to said hydraulic means for selectively applying hydraulic power thereto, and pressure operated valve means connected to said hydraulic lines to said first and second hydraulic means for automatically interconnecting the hydraulic lines to said first and second hydraulic means whereby, upon increase in pressure in said second hydraulic means caused by an impediment to motion of said bucket, said hydraulic lines to said first and said second hydraulic means are interconnected to activate said first hydraulic means.

References Cited in the file of this patent UNITED STATES PATENTS 

